Magnesium Lithospermate B Downregulates the Levels of Blood Pressure, Inflammation, and Oxidative Stress in Pregnant Rats with Hypertension

Magnesium Lithospermate B Inhibits Colorectal Cancer Cell Progression Through JAK2-STAT3 Signaling

Colorectal cancer (CRC) is the third most commonly diagnosed cancer and the second leading cause of cancer death worldwide. The discovery of new effective therapeutic drugs is always a priority. Magnesium lithospermate B (MLB), a native polyphenol acid, is the major component of the aqueous extracts from Danshen, a traditional Chinese medicine derived from the dry root and rhizome of Salvia miltiorrhiza. MLB has been reported to have antioxidant, anti-inflammatory, and ion channel-regulating activities in several diseases, including cardiovascular, renal, and neuronal diseases. However, the effect of MLB on cancer progression has not been reported. In this study, a series of cellular and molecular experiments were conducted on two CRC cell lines (HCT116 and SW480) to investigate the effects of. The results demonstrated that MLB exerted inhibitory effects on cell proliferation, migration, and invasion. The administration of 50 mg/kg MLB inhibited tumor growth in HCT116 cells in xenografted models. Importantly, we found that MLB treatment inhibited the Janus kinase 2 (JAK2)-signal transducer and activator of transcription 3 (STAT3) signaling pathway, and activation of JAK2-STAT3 signaling with interleukin 6 or overexpression STAT3 significantly suppressed the inhibitory effect of MLB. These findings provide evidence that MLB could inhibit CRC cell progression in vitro and might serve as a potential therapeutic drug for the treatment of CRC.

Effects of apelin on neonatal brain neurogenesis in L-NAME-induced maternal preeclampsia

The aim of this study was to investigate the possible protective effects of apelin, which is known to have antioxidant and anti-inflammatory effects, on changes in neurogenesis in newborns of pregnant rats with L-NAME-induced preeclampsia. Wistar albino female rats were divided into four experimental groups: Control, Apelin, Preeclampsia and Preeclampsia + Apelin. Blood pressure was measured on the 5th, 11th and 17th days of gestation, urine protein was analyzed from urine samples collected for 24 h on the 6th, 12th and 18th days and serum creatinine was analyzed from serum samples. Maternal kidney and placenta tissues were obtained to establish the preeclampsia model, and neonatal brain tissues including the cortex, hippocampus and cerebellum regions were obtained to investigate neurogenesis and examined by histological and immunohistochemical methods. The number of newborns, body weight and brain weight of the newborns were measured. eNOS, IL-10, nNOS and NO levels in the brain analyzed via ELISA. Mean arterial pressure, urine protein and serum creatinine increased in the preeclampsia. Newborn weight decreased in the Preeclampsia group, the values in the Preeclampsia + Apelin group were closer to the Control and Apelin groups. In the Preeclampsia group, edema and dilatation in the proximal and distal tubules of kidneys, perivillous fibrin deposition and increase in syncytial nodules of placenta were observed. VEGF immunoreactivity decreased and iNOS immunoreactivity increased in both kidney and placenta. In neonatal brain tissue examinations, cytotoxic edema accompanied by thinning of cortex, delayed migration and lower cell counts in the hippocampus, and increase in intercellular spaces and EGL thickening in the cerebellum were observed in the preeclampsia. Expression of NeuN, GFAP, MBP, IL-10, eNOS, nNOS and NO levels decreased, whereas expression of Iba-1 increased in the preeclampsia. In the Preeclampsia + Apelin group, these findings were similar to the Control and Apelin groups. Apelin administration was found to be beneficial for preventing the adverse consequences of preeclampsia, but further experimental and clinical studies are needed to better understand these effects.

Paeoniflorin alleviates NG-nitro-L-arginine methyl ester (L-NAME)-induced gestational hypertension and upregulates silent information regulator 2 related enzyme 1 (SIRT1) to reduce H2O2-induced endothelial cell damage

Pregnancy-induced hypertension (PIH) is a leading cause of maternal mortality. Paeoniflorin has been reported to alleviate hypertension, thus relieving the injury of target organ. This study aimed to investigate the role of paeoniflorin in PIH development by regulating SIRT1 in rats. The mean arterial pressure (MAP), urine protein and histopathological damage of placenta in gestational hypertension rats were, respectively, detected by noninvasive tail-artery pressure measuring instrument, BCA method and H&E staining. The viability of human umbilical vein endothelial cells (HUVECs) treated with paeoniflorin or/and H₂O₂ was observed by CCK-8 assay. SIRT1 protein expression in HUVECs treated with paeoniflorin or/and H₂O₂ was analyzed by Western blot. Tunel assay, wound healing assay and tube formation assay were used to detect the apoptosis, migration and tube formation of HUVECs administrated with paeoniflorin or/and H₂O₂ or/and EX527 (SIRT1 inhibitor). As a result, MAP, urine protein and histopathological damage of placenta were enhanced in PIH rats, which were then alleviated by paeoniflorin. Paeoniflorin decreased the levels of sFlt-1, PlGF and VEGF in serum and placental tissues of gestational hypertension rats as well as the inflammatory response and oxidative stress. In addition, paeoniflorin promoted the expressions of SIRT1 and NO/eNOS and inhibited the production of iNOS in gestational hypertension rats to improve vascular endothelial cell injury. However, SIRT1 inhibition could suppress the protective effects of paeoniflorin on endothelial dysfunction of H₂O₂-induced HUVECs. In conclusion, paeoniflorin could improve gestational hypertension development by upregulating SIRT1.

Mechanism for Cas4-assisted directional spacer acquisition in CRISPR-Cas

Prokaryotes adapt to challenges from mobile genetic elements by integrating spacers derived from foreign DNA in the CRISPR array¹. Spacer insertion is carried out by the Cas1-Cas2 integrase complex^2-4. A substantial fraction of CRISPR-Cas systems use a Fe-S cluster containing Cas4 nuclease to ensure that spacers are acquired from DNA flanked by a protospacer adjacent motif (PAM)^5,6 and inserted into the CRISPR array unidirectionally, so that the transcribed CRISPR RNA can guide target searching in a PAM-dependent manner. Here we provide a high-resolution mechanistic explanation for the Cas4-assisted PAM selection, spacer biogenesis and directional integration by type I-G CRISPR in Geobacter sulfurreducens, in which Cas4 is naturally fused with Cas1, forming Cas4/Cas1. During biogenesis, only DNA duplexes possessing a PAM-embedded 3'-overhang trigger Cas4/Cas1-Cas2 assembly. During this process, the PAM overhang is specifically recognized and sequestered, but is not cleaved by Cas4. This 'molecular constipation' prevents the PAM-side prespacer from participating in integration. Lacking such sequestration, the non-PAM overhang is trimmed by host nucleases and integrated to the leader-side CRISPR repeat. Half-integration subsequently triggers PAM cleavage and Cas4 dissociation, allowing spacer-side integration. Overall, the intricate molecular interaction between Cas4 and Cas1-Cas2 selects PAM-containing prespacers for integration and couples the timing of PAM processing with the stepwise integration to establish directionality.